Which class of antibody decreases with stress?

• A. IgM
• B. IgE
• C. IgD
• D. IgA

Answer: (D)

The correct choice is based on the function and response of the immune system during stressful conditions. Immunoglobulin A (IgA) plays a crucial role in mucosal immunity and is primarily found in secretions such as saliva, tears, and mucous membranes. It acts as the first line of defense against pathogens entering through mucosal surfaces.

Research has shown that stress can negatively impact the immune system, often leading to a decrease in the production of IgA. Elevated stress levels can cause the body to release hormones like cortisol, which can suppress immune function, including the synthesis of IgA. This reduction in IgA can make an individual more susceptible to infections, particularly those that enter via mucosal surfaces.

In contrast, other classes of antibodies such as IgM, IgE, and IgD do not exhibit a consistent decrease in response to stress in the same way that IgA does. Understanding the role of IgA can illuminate how stress influences immune responses and the importance of maintaining mucosal immunity in high-stress situations.